Successive ionisation energy of an atom is greater than previous one, because:

Options

A. `p/e` ratio increases
B. `p/e` ratio decreases
C. `p/e` ratio remains constant
D. none of these

Explanation

To understand why the successive ionization energy of an atom is greater than the previous one, we can break down the explanation step by step:

### Step-by-Step Solution:

1. **Definition of Ionization Energy**:
- Ionization energy is defined as the amount of energy required to remove an electron from a gaseous atom or ion.

2. **First Ionization Energy**:
- The first ionization energy is the energy required to remove the highest energy electron from a neutral gaseous atom. For example, when sodium (Na) is ionized, it loses one electron to form Na⁺.
- The first ionization energy for sodium is approximately 496 kJ/mol.

3. **Second Ionization Energy**:
- The second ionization energy is the energy required to remove an electron from a singly charged cation (Na⁺). This process results in the formation of Na²⁺.
- The second ionization energy for sodium is significantly higher, around 4560 kJ/mol.

4. **Reason for Increasing Ionization Energies**:
- The increase in ionization energy with each successive removal of an electron can be attributed to the change in the ratio of protons to electrons (P/E ratio).
- As electrons are removed, the number of electrons decreases while the number of protons remains constant. This leads to a higher positive charge per electron, which increases the attraction between the remaining electrons and the nucleus.

5. **Conclusion**:
- Therefore, the successive ionization energy of an atom is greater than the previous one because the ratio of protons to electrons increases, leading to a stronger attraction between the nucleus and the remaining electrons.